1. Works by exploiting the ability of a given mRNA molecule to hybridize to the DNA template that it originated from.
2. Can measure the amount of gene expression in cell by recording the amount of mRNA bonded to each DNA site on an array.
3. This amount of bonded mRNA is recorded with computer technology and a gene expression profile is set up.
B. Human Genome
1. Considered the complimentary partner to microarrays.
2. Human Genome is the knowledge and microarrays are the technology.
a. Without the human genome project microarrays would be dubbed useless.
b. Currently using microarrays to organize and catalog parts of the human genome.



They work by identifying tagged healthy and unhealthy cells. They show which genes are turned on and being used compared to those that are turned off and are unused. The tested cells RNA is isolated and tagged with fluorescent tags and then used to make DNA. The specific DNA that the mRNA creates is cDNA. The cDNA is then applied to the microarray. The cDNA hybridizes to the complementary base pairs on the of spot of the microarray. The microarray is then scanned and the colors show which cells are expressing what genes. Expression charts are created from the data and then can be used later which will be explained more in a little bit.

flowchart.gifmicroarray-experiment.jpg

Also, without the human genome project being complete microarrays would be almost useless. Microarrays depend upon the human genome project to determine what genes have what base pair sequence, and knowing the base pair sequence allows for the changing of mRNA to cDNA and helps with determining what each gene codes for if it codes for anything. The use of microarrays working with the human genome project could potentially lead up to the discovery of new drugs to fend off cancer and such diseases as AIDS and other viruses that have proven to be deadly.